Microsoft Office is the Tonto to Windows’ Lone Ranger—it gets beat up and disparaged by the townsfolk, but in the end it saves Windows’ bacon over and over. While Windows releases are shiny, hype-inflated events, Office does the dirty work of getting users comfortable with each new generation of user interface changes. Office provides the features that gradually convince OS holdouts to move on (well, at least as soon as Service Pack 2 ships).

That role is especially heightened for Office 2013, the next version of Office being unveiled today at an event in San Francisco (where CEO Steve Ballmer said, "We feel a lot like it's 1995." You can interpret for yourself now that the preview is live, available at office.com/preview). Ars got an advance preview of the vastness of Office 2013; Peter Bright and I have spent the last week mapping its previously unknown territory. Some areas of the suite remain Terra Incognita, mostly because Microsoft didn't have everything quite ready for the press to look at in advance of the super-top-secret unveiling, but the suite's basic outlines are now clear.

Some applications have gotten a fresh coat of paint and not much in the way of new functionality. That's subject to change; Lync and OneNote, for example, are far from the final form they'll take when they ship. Other programs have received a raft of feature tweaks and incremental innovations that make them significant enough improvements to warrant an upgrade. But we found that the most dramatic changes were not in any application-specific feature, but in the structure and packaging of the whole. Microsoft has tightly bound cloud, Internet services, and social networking to the Office platform.

Microsoft has also fundamentally changed how most consumers and businesses will buy the package: not as a one-shot disk in a box but as a streamed subscription service.

The changes are part of a much bigger strategic shift for Microsoft. Office 2013 is more than just a refresh of Microsoft’s nearly ubiquitous productivity applications. Microsoft is clearly counting on Office 2013 to be a fulcrum point for the company’s whole Windows and cloud platform strategy: moving from a PC-centric worldview to an ecosystem of devices; moving from older Windows versions to Windows 8; and moving from software sales toward cloud-driven subscriptions.

While Windows 8 may be the big circus tent in that strategy, Office makes up most of the tent poles:

To lift Microsoft’s mobile and tablet aspirations, components of Office will be baked into every Windows RT device, and versions of the core applications will be available for Windows Phone.

To coax adoption of Windows 8 on the PC, Microsoft is offering enhanced features (particularly around touch and pen-based interfaces) on the new operating system, and Metro versions of two applications to show off the potential of the Metro interface.

To give third-party service developers and channel partners a better way to build add-on services to Office (and generate continuous revenue), Microsoft has created a new Office service integration API (code-named Agave) based on HTML5 and JavaScript, while keeping the legacy Visual Basic for Applications support intact.

And by offering Office as part of a subscription service tied to the Office 365 platform—both for consumers and businesses—Microsoft hopes to preserve its desktop dominance against other cloud-based challengers like Google Apps and to fundamentally change the economics of its application software business.

As a result, Office 2013 looks like a bridge between Microsoft’s legacy desktop world and the company’s vision of a hybrid client/cloud future. Hey, Office team: no pressure, right?

To effectively test the preview of Office, we installed it on a number of platforms: Samsung Windows 8 tablets were provided on loan by Microsoft for testing the Office tablet experience, and we installed the suite on Windows 8 and Windows 7 desktops as well. The preview also included accounts on a pre-release version of the updated Office 365 Web service, and Peter Bright and I both connected our installations to our "legacy" Exchange environments for testing. A number of things weren’t cooked in time for our preview, but they were teased by Microsoft in a private demo; we couldn't test them, so I've mentioned them only briefly.

We’ll present separate previews of each of the major Office 2013 applications, but in this article, I’ll take a broader look at the suite as a whole, including the revamped Office 365. The idea is to find out whether Office 2013 can effectively bridge all of the pieces of Microsoft’s platform strategy—or whether it’s a bridge to nowhere.

The answer to that question depends on whether you share Microsoft’s vision of a Windows-driven world. Many organizations will benefit in some way from drinking Microsoft’s Windows/Office/Cloud kool-aid, but the changes here may also evoke the same confusion among users that came out of Microsoft’s last major Office interface change in 2007. For others who upgraded two years ago (or sooner), however, the changes may not be compelling enough to upgrade—or to pick Microsoft over another cloud solution.

Enlarge/ The ten tiles of Office 2013, plus a link to the Office 365 service. Silverlight photobombed the group shot.

The Office vision quest

Planning for Office 2013 began in parallel with the Windows team’s planning for Windows 8, said Microsoft Vice President for Office P.J. Hough during a private briefing on the new Office platform. "When we started planning," Hough told me, "we were both sampling the market to determine which big shifts we wanted to take advantage of."

That parallel planning resulted in both teams focusing on three major areas. The first was what has infamously become known as the "consumerization of IT"—including the rise of mobile devices and tablets. "Before any of the current generation of tablets had shipped, we saw this opportunity in the proliferation of devices," Hough said. Whatever the Office team did, it needed to embrace mobile devices and tablets—not just x86 tablets, but ARM devices and phones as well.

Microsoft had an internal debate over whether touch or voice recognition would be the next important interface. Touch won out, both on the Windows 8 and Office teams, and that choice heavily influenced the design of the application interfaces for the Office apps—they needed to work well both as traditional PC applications with mouse and keyboard, and as touch (and pen) applications on tablets.

Both the Windows and Office teams also saw "a lot of opportunity around people and social networks," Hough said, "both in consumer and with the leading edge starting to encroach on the enterprise." That interest in social networking has already expressed itself through Microsoft’s recent acquisition of Yammer and its continuing relationship with Facebook.

Some social networking integration had already worked its way into Office through Outlook’s “Social Connector” integration with its contact management. But Office 2013 takes social networking and collaboration features even further, integrating them into the interface of most of the Office applications. Microsoft has also added social network-like features such as “following” and status updates to a revamped version of the Office 365 cloud service now in preview.

But perhaps the biggest trend that Microsoft wanted to build deeper into Office was cloud and Internet services. Hough said that Microsoft had already heavily invested in the cloud during in Office’s last generation—through services like Office 365 and SkyDrive. But in the new version of Office, cloud and Internet services (both Microsoft’s and those of its partners) are front and center. Perhaps the most obvious way that this has happened is in the evolution of how Microsoft plans to distribute Office 2013: as a subscription service, streamed from the cloud.

Sean Gallagher / Sean is Ars Technica's IT Editor. A former Navy officer, systems administrator, and network systems integrator with 20 years of IT journalism experience, he lives and works in Baltimore, Maryland.